You all know that agricultural crop production relies on fertilizers, such as composted waste materials. But I bet you wouldn't have thought to add human hair to animal manure to produce better and greener fertilizers. Yet, a study done by Mississippi State University researchers has shown that human hair, 'combined with additional compost, is an additional nutrient source for crops.' Apparently, barbershops and hair salons are selling human hair for a couple of years now -- a fact I didn't know. Anyway, even if human hair can be used to grow some plants, 'further research is necessary to determine whether human hair waste is a viable option as fertilizer for edible crops.' ...
This research project has been led by Dr. Valtcho Jeliazkov (Zheljazkov), an Assistant Research Professor at Mississippi State University and a member of the North Mississippi Research and Extension Center.
How Zheljazkov and his colleagues conducted this research? "The study compared the productivity of four crops: lettuce, wormwood, yellow poppy, and feverfew, grown in commercial growth medium using untreated control, noncomposted hair cubes at differing weights, a controlled-release fertilizer and a water-soluble fertilizer. Results showed that, with the addition of hair waste cubes, yields increased relative to the untreated control but were lower than yields in the inorganic treatments, suggesting that hair waste should not be used as a single source for fast-growing plants such as lettuce."
And here is a short quote from Zheljazkov about why human hair can be efficiently used to feed plants. "Once the degradation and mineralization of hair waste starts, it can provide sufficient nutrients to container-grown plants and ensure similar yields to those obtained with the commonly used fertilizers in horticulture. However, it takes time for the hair to start degrading and releasing nutrients, as is reflected in lower yields in the hair treatments relative to the inorganic fertilizers for lettuce and wormwood."
This research work has been published by HortTechnology under the title "Human Hair as a Nutrient Source for Horticultural Crops" (Volume 18, Issue 4, Pages 592-596, October-December 2008).
Here are some excerpts from the abstract. "Two pot experiments were conducted to evaluate noncomposted hair byproduct as a nutrient source for container-grown crops. Lettuce (Lactuca sativa 'Green Leaves') and wormwood (Artemisia annua 'Artemis') were grown in a commercial growth substrate amended with 0%, 2.5%, 5%, or 10% by weight hair waste or controlled-release fertilizer (CRF) or were watered with a complete water-soluble fertilizer (WSF). After harvest, yellow poppy (Glaucium flavum) was grown in the pots and substrate that previously grew wormwood, and feverfew (Tanacetum parthenium) was grown in the pots and substrate previously containing lettuce. [...] Yields in treatments containing hair or CRF or watered with WSF were higher than in the untreated control. The highest lettuce and wormwood yields occurred with CRF followed by WSF and 5% and 10% hair treatments. [...] Results from this study suggest that noncomposted hair waste could be used as a nutrient source for container-grown plants."
On a very similar subject, you also can read a paper written by Zheljazkov and other colleagues for the Agronomy Journal, "Uncomposted Wool and Hair-Wastes as Soil Amendments for High-Value Crops" (Volume 100, Issue 6, Pages 1605-1614, November-December 2008).
Here are some excerpts from the abstract."The hypothesis of this work was that uncomposted sheep wool and human hair could be used as nutrient source for nonedible high-value plants. Pot and field experiments were conducted to assess uncomposted sheep wool-wastes and human hair-wastes as a nutrient source for high-value crops and to evaluate the effect of these waste materials on soil microbial community and mycorrhizae. [...] Our results suggest that the addition of uncomposted wool-waste or hair-waste of only 0.33% by weight to soil would support at least 2 to 3 harvests of crops, without the addition of other fertilizers. Uncomposted wool and hair-wastes can be used as a nutrient source for high-value crops."
Finally, if you think that these scientists are somewhat crazy to use human hair as an ingredient to create better crops, please read this page about a Canadian gardener using human hair to fight deers and tell me what you think -- I don't guarantee that human hair can stop deers to eat salads!
Sources: American Society for Horticultural Science (ASHS) news release, December 29, 2008; and various websites
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